Vibrating screen



June 14, 1966 .1. P. BURLS 3,255,885

VIBRATING SCREEN Filed Feb. 27, 1963 2 Sheets-Sheet 1 INVENTOR June 14,1966 J. P. BURLS 3,255,835

VIBRATING SCREEN Filed Feb. 27, 1965 2 Sheets-Sheet 2 INVENTOR Jaw FEW/$i mkr fix/far X/IZ/i i.

United States Patent 3,255,885 VIBRATING SCREEN John I". Burls,Johannesburg, Transvaal, Republic of South Africa, assignor to NordhergManufacturing Company, Milwaukee, Wis, a corporation of Wisconsin FiledFeb. 27, 1963, Ser. No. 261,397 3 Claims. (Cl. 209314) This inventionrelates to an improved horizontally disposed vibrating screen.

A primary purpose of the invention is a vibrating screen which is soformed that the material being screened tends to tumble as it movesalong the screen deck to thereby offer different faces of each particleto the screen.

Another purpose is a vibrating screen made up of a plurality of inclineddeck sections, with the discharge end of each section being positionedabove the feed end of the next lower section.

Another purpose is a vibrating screen formed of a plurality of inclineddeck sections in which each section un- ,dulates in a directionperpendicular to the axis of vibration.

Another purpose is a screen of the type described in which the screendeck sections are formed by alternate troughs and crests, with thetroughs of one deck section being aligned with the crests of theadjacent deck section.

Other purposes will appear in the ensuing specification, drawings andclaims.

The invention is illustrated diagrammatically in the following drawingswherein:

FIGURE 1 is a side View of a vibrating screen of the type described,

FIGURE 2 is a top plan view of the screen shown in FIGURE 1,

FIGURE 3 is an enlarged partial perspective of a vibrating screen of thetype described showing one formation of the screen deck sections, and

FIGURE 4 is an enlarged perspective, similar to FIG- URE 3, showinganother formation of the screen deck sections.

Considering FIGURE 1, the base of the screen may include a pair of sideframe members or channels mounted on front supports 12 and a laterallyextending rear support 14. A laterally extending cross member 16 mayhold the front end of the channels together and a pair of spaced crossmembers 18 may hold the rear end of the channels together.

The deck for screening material, whether it be ore or otherwise, may beformed of a plurality of screen deck sections indicated generally at 20and shown particularly in FIGURES 2, 3 and 4. Each of the sections willbe described in detail hereinafter. The sections are each mounted withina framework 21 consisting of generally vertically extending supports 22tied together at their upper ends by generally downwardly slopingmembers 24. Each of the deck sections 20 is supported in the framework21 by straps or the like, indicated at 26, with the upper end of thestraps being fastened to the members 24. The front end of the lower decksection may be supported by a cross member 40, as shown in FIGURE 2. Theframe, which may also include side plates 27, will be mounted on thebase by rubber mounting members 36, at the front, and by suitablesprings, not shown, at the rear. The rubber mounting members are solidand may be formed of a dual hardness rubber.

Positioned above the first of the deck sections 20, or the highest decksection, is a feed chute 28, the rear end of which is supported byupwardly extending supports 30. The underside of the feed chute issupported by frame members 32. Beneath the feed chute 28 is a drivemechanism the shaft of which is indicated at 34. Although the particularlocation of the drive mechanism is not essential to the invention, ithas been found to be advantageous to place the drive unit at the rear ofthe structure. The drive may be conventional and will provide rapidvibrations in a generally longitudinal direction to move the materialbeing screened from the feed chute toward the discharge or front end.

Beneath the deck sections is a discharge chute 38 which receivesmaterial passing through the deck sections and discharges it down to asuitable hopper or the like, not shown.

FIGURE 3 illustrates one formation of the screen deck sections 20. Eachsection may undulate in a direction perpendicular to or transverse tothe direction of vibration, which is longitudinal, with each sectionbeing formed by a plurality of spaced upwardly open troughs 42 separatedby crests 44. The crests 44 may be capped, by metal plates or the like46. The plates 46 are important as they protect the underlying platesfrom the impact of heavier and larger pieces of material.

As shown in FIGURE 3, each of the screen deck sections is formed of aperforated or expanded metal, a woven wire mesh, or a foraminousmaterial having openings 48 for the passage of the material beingscreened. The size of the openings 48 is substantially less than thewidth of the troughs. The particular design for each of the decksections will depend upon the type and size of material being screened.Expanded or perforated metal sections may be used for smaller sizematerial.

As illustrated particularly in FIGURE 3, the troughs 42 of each screendeck section are aligned with the crests 44 of the adjacent section. Inthis way, material sliding down the trough of one section will tumblewhen it reaches the end of that section in that it must go either to theright or to the left in order to reach the trough of he next lowersection. Also note that the trough of one section is substantially belowthe trough of the section next above it. The crest of one deck sectionand the trough of the preceding section may be generally the sameheight, although again this is not necessary and the crest of onesection may be below the preceding trough. In any event, what isimportant is to provide an alignment such that material being screenedwill tumble and roll as it passes along the screen, thereby presentingdifferent sides of each particle to the screen structure. It is in thisway that the fines which may stick to the larger material will beremoved during the screening process.

FIGURE 4 illustrates another formation of the deck sections. In thiscase spaced parallel rods 50, supported at opposite ends by formed barsor rods 52, are arranged in a configuration substantially like thatshown in FIGURE 3. Each deck section undulates or is sinuous in adirection transverse to the axis of vibration with the crests in onesection being aligned with the troughs in the adjacent sections. Theinvention should not be limited to any particular formation of the decksections as what is important is to provide openings for the screeningof material, with the formation itself being in the general shape of aseries of waves, with the troughs of one section being aligned with thecrests of the adjacent sections.

The use, operation and function of the invention are as follows:

One of the disadvantages of previous screens in which the deck wassubstantially flat, was that larger pieces of material being screenedtended to maintain a fixed orientation as they moved through thescreening zone. The same surfaces of each particle contacted the screen.Accordingly, any undersized particles adhering to the larger particlesoften were carried along with them and the screening process was notefiicient. To overcome this difficulty it is proposed to tumble and rollthe particles so that substantially all of the surfaces .of each of theparticles will contact the screen at some point thereby removing asubstantial portion of the adhering undersized particles.

By dividing the screen deck into a plurality of sections, each inclined,and by making it mandatory that each particle drop and laterally move asit falls from one section to another, it is possible to provide 'atumbling or rolling motion for the mass of particles as they passthrough the screening zone. The screen deck sections are formed intotroughs which open upwardly, with crests separating each of the troughs.The crests of one deck section are aligned with the troughs of theadjacent deck sections thereby insuring tumbling movement of the mass ofmaterial as it passes through the screening zone. This promotes theremoval of the undersized particles that adhere to the larger particles.

- An additional advantage from the undulating deck-section is the addedarea available for screening.

The particular formation of each of the deck sections is not importantand a plurality of steel rods, suitably spaced, may be used as well asperforated or expanded metal or woven wire mesh. Spaced bars are alsosatisfactory. What is important is the over-all configuration of each ofthe deck sections and not the type of opening.

The size of the openings may vary considerably, depending on thematerial being screened. For example, l /z-inch openings may besatisfactory for one type of operation and openings as small as 4 inchor A1 inch may be satisfactory for other operations.

The present invention is used in a machine in which vibration isprovided in a generally longitudinal directo further screen the materialor to screen out an inter- Also, Water may be directed upwardly mediatesize. at the deck sections to increase the separation efficiency.Whereas the preferred form of the invention has been shown and describedherein, it should be realized that there are many modifications,substitutions and alterations thereto within the scope of the followingclaims.

I claim:

1. In a vibrating screen, a base, a deck supported on said base andmeanson the base for vibrating said deck along an axis extendinggenerally longitudinally of said deck, said deck including a pluralityof sections arranged end to end and inclined downwardly toward thedischarge end of the deck, each such section having a plurality ofparallel, upwardly open troughs extending along the axis of vibration ofthe screen, and separate-d by crests, the walls of the troughs beingformed with apertures of substantially smaller diameter than the widthof the troughs through which undersize material may escape, areinforcing plate capping each crest, the feed end of each lower sectionbeing offset downwardly in relation to the discharge end of each uppersection, with the troughs in adjacent sections being staggered, where bymaterial delivered from the discharge end of the troughs of a givensection is directed downwardly toward crests of the next section.

2. The structure of claim 1 further characterized in that the troughsare formed of foraminous material.

3. The structure of claim 1 further characterized in that the troughsare formed of a plurality of parallel rods.

References Cited by the Examiner UNITED STATES PATENTS 222,360 12/ 1 879Merrifield 2093 15 268,491 12/1882 Hubbell 209397 843,785 2/1907 Allen209--393 X 1,026,529 5/1912 Rainforth 209393 1,032,746 7/1912 Evans209-393 1,269,085 6/1918 Jeske 2093l4 1,595,685 8/1926 Parini 2093922,225,095 12/1940 Beverly 241-88 2,973,865 3/1961 Cibula 209-392 FOREIGNPATENTS 671,819 2/1939 Germany;

1,129,121 5/1962 Germany.

HARRY B. THORNTON, Primary Examiner.

HERBERT L. MARTIN, Examiner.

R. HALPER, Assistant Examiner.

1. IN A VIBRATING SCREEN, A BASE, A DECK SUPPORTED ON SAID BASE ANDMEANS ON THE BASE FOR VIBRATING SAID DECK ALONG AN AXIS EXTENDINGGENERALLY LONGITUDINALLY OF SAID DECK, SAID DECK INCLUDING A PLURALITYOF SECTIONS ARRANGED END TO END AND INCLINED DOWNWARDLY TOWARD THEDISCHARGE END OF THE DECK, EACH SUCH SECTION HAVING A PLURALITY OFPARALLEL, UPWARDLY OPEN TROUGHS EXTENDING ALONG THE AXIS OF VIBRATION OFTHE SCREEN, AND SEPARATED BY CRESTS, THE WALLS OF THE TROUGHS BEINGFORMED WITH APERTURES OF SUBSTANTIALLY SMALLER DIAMETER THAN THE WIDTHOF THE TROUGHS THROUGH WHICH UNDERSIZE MATERIAL MAY ESCAPE, AREINFORCING PLATE CAPPING EACH CREST, THE FED END OF EACH LOWER SECTIONBEING OFFSET DOWNWARDLY IN RELATION TO THE DISCHARGE END OF EACH UPPERSECTION, WITH THE TROUGHS IN ADJACENT SECTIONS BEING STAGGERED, WHEREBYMATERIAL DELIVERED FROM THE DISCHARGE END OF THE TROUGHS OF A GIVENSECTION IS DIRECTED DOWNWARDLY TOWARD CRESTS OF THE NEXT SECTION.